The term direct detection of hydrocarbons was used 50 years ago by I. G. Medovsky. He, apparently, was the first to connect increased attenuation of seismic waves with oil and gas fields. During last 20 years, we have conducted extensive experimental research, on well data and surface data, and measured the abnormal attenuation and velocity dispersion (AVD) of seismic waves in oil and gas fields. In all experiments, the deviation from theoretical elastic wave propagation was so high that we named this effect seismic inelasticity of oil and gas fields.

Our main finding is experimental confirmation that both attenuation and...